Fluid jet relay



2 Sheets-Sheet l nven tors Tf1/cz Zzfer' L. Benedict Szdney Finn Mardi 16, 1954 w. BENEDICT ET AL FLUID JET RELAY Filed Aug. 25, 1951 March 16, 1954 w. l.. BENEDICT ET AL 2,672,150

FLUID JET RELAY Filed Aug. 25, 1951 2 Sheets-Sheet 2 Patented Mar. 16,1954

UNITED STATES PATENT OFFICE FLUID JET RELAY Walter L. Benedict, Stoneham, and Sidney J. Finn, Beverly, Mass., assgnors to United Shoe Machinery Corporation, Flemington, N. J., a corporation of New Jersey Application August 25, 1951, Serial N o. 243,641

14 claims. (o1. 137-83) This invention relates to fluid jet relays and the thermal expansion of the several parts so that has for its principal object the provision of a an extremely close operating clearance may be novel and improved fluid jet relay which is highly maintained between the jet nozzle and the reeilicient, extremely sensitive and very dependable ceiver member, thereby substantially increasing in operation. the eiciency of the relay. More particularly, the

Fluid jet relays, as hitherto constructed, usually jet nozzle of the relay is carried by a pipe which include a jet pipe, formed with a discharge nozzle, is mounted on a header block and this header and a receiver member, provided with two openblock, in turn, is supported on a base member ings for receiving iluid under pressure delivered by means of a pair of conduits which extend upthereto from the jet nozzle, these parts being asl wardly from the base member. Surrounding the sociated with a housing, on which the jet pipe is base member, on which the receiver block is suppivotally mounted, with suitable connections for ported, and extending upwardly therefrom, is a admitting fluid under pressure to the jet pipe housing, and the header block is slidably tted in and for conducting the pressure nuid received by the upper end of 'this housing. The two conduits the openings in the receiver member to the opl5 which support the header block and the pipe posite ends of a reversible Huid pressure motor which carries the jet nozzle are constructed of such, for example, as a piston cylinder. These materials having substantially the same linear devices are also provided with means for displaccoefficient of expansion so that, as the temperaing the jet nozzle, relatively to the two openings, ture of the operating uid increases, these parts thereby to effect an unbalancing of the pressure expand by the same amount and the operating of the fluid delivered to the motor so as to cause clearance between the jet nozzle and the receiver it to operate in one direction or the other at a block will remain the same. Accordingly, the rate proportional to the extent of displacement operating clearance between the jet nozzle and of the jet nozzle. Fluid jet relays of this type the receiver block can be reduced to an absolute are well known and are frequently used as comminimum which will be unchanged by temperaponent parts of servo mechanisms in which there ture variations during the operation of the relay. are included so-called feed-back connections for Because of the extremely small operating clear' restoring the jet nozzle to a centered position, ance which is thus provided, the efficiency of the relatively to the receiver openings, in response jet relay is very greatly increased. to operation of the fluid motor. In accordance with another feature of the in- While uid J'et relays of the type just described vention, the flexibility of the pipe which carries are used quite Widely for various purposes, they the jet nozzle is utilized to permit displacement are not entirely satisfactory under all conditions, of the nozzle relatively to the openings in the particularly where a high eiciency and extreme receiver block thereby eliminating the disadvansensitivity must be coupled with dependability of tages resulting from the use of frictional bearoperation. For example, in order to compensate ings. Thus, the pipe which supports the nozzle for the unequal thermal expansion of the various and is adjustably mounted at its upper end in the parts when the operating fluid, such as oil, beheader block, comprises a metallic tube of concomes heated during the operation of the jet residerable length. The jet nozzle is secured dilay, it has been necessary to provide a substantial 40 rectly to the lower end of this tube with its disoperating clearance, between the jet nozzle and charge orice directly over and closely adjacent the receiver member, which materially decreases to the receiver block. With this arrangement, the eiciency of the device. Also, because of displacement of the jet nozzle, relatively to the static friction in the bearings of which the jet Openings in the receiver b10ck,may be effected by nozzle is pivotally mounted, a certain stickiness slightly bending the ilexible jet pipe without any of action may result which not only requires the stickiness or frictional resistance such as would application of a considerable force initially to be present if the jet pipe were supported in beardisplace the nozzle and thereby greatly decreases ings.

the sensitivity and response of the relay, but also Preferably, and as herein illustrated, spring renders the relay somewhat undependable in opmeans are provided for accurately centering the eration. jet nozzle, relatively to the openings in the re- With the view of overcoming these dinculties, ceiver block. This spring means operates directly the herein illustrated jet relay, in accordance on the jet nozzle which, due to the considerable with a feature of this invention, provides an arlength and flexibility of the jet pipe, acts more rangement for automatically compensating for or less like a free body and responds most readily Fig. l is a view in elevation of ajet relay embodying the features of this invention, with certain parts broken away and others shown. in.

section;

Fig. 2 is a view in elevation of the lower portion of the jet relay, with certain parts shown insection substantially on lineV lli-IE. of Fig. l and looking in the direction of the arrows;

Fig. 3 is a plan view of the lower portion of the `iet relay, with certain parts shown in section, substantially on line lll-'HI in Fig. l and looking in the direction of the arrows;

Fig. 4 is a plan view of a lower portion of the jet relay shown at an enlarged scale and with certain parts in section substantially on lines V-IV of Fig. 2 and looking in the direction of the arrows;

Fig. 5 is a sectional View of a portion of the lower part of the jet relay substantially on line V-V of Fig. 4 looking in the direction of the arrows; and

Fig. 6 is a schematic plan view of certain parts ofthe jet relay at a greatly enlarged scale.

Referring to these-drawings, and particularly to Fig. l thereof, the jet relay therein illustrated comprises a cylindrical housing lil, a base inember l?. on which there is supported a receiver block lll, a header block l@ which is supported on the base member by means of a pair of conduits i8, i8, and a jet pipe 2d provided with a jet nozzle 22. The base member i2 is secured to the lower end of the housing lli by means of screws 24, 2d` which pass through a flange E@ on the base member and are threaded into the housing. At its upper end, the housing is closed by a. cover plate 28, secured to the lhousing by screws 30, Sil and provided with a central bore 32. At their opposite ends, the conduits E3, i8 are force-fitted and sweated into bores 34, Eiland Se, formed respectively in the base member l2v and in the header block l, while the header block is slidably fitted in the central bore Si?. of the cover plate 28 which forms the upper end of the housing. The upper end of the jet pipe 2e is similarly secured in a bore 3B formed in a cylindrical member lil which is fitted in a bore i2 in the header block. The member dil has a radially extending flange lll and is secured to the header block by means of screws d6, 4G, passing through this flange. It is important that the conduits ld, i3 be positively locked to the base member if. and header block i5 and that the pipe 2li be fixed to the member with equal security. For this purpose the force tting andV sweating. together of these parts may be supplemented by pins, not shown.

The bores 34, 35i, in the base member, are connected to an inlet pipe 5@ by means of a pair of angularly disposed intersecting boresl 52., 52,

which are plugged at their outer ends, and a radial bore 5 4, Fig. 4. The inlet pipe extends drawings and will be through the housing l0 and is secured thereto by means of a flange 5e and screws 58, 58, Fig. 3. The bores 3S, 36, in the header block l5, are connected, by radial ports e0, 6d, to an annular groove 52, formed in the cylindrical member lili, and this groove, in turn, is connected to the bore 38 and the jet pipe 2li, by means of radial ports lid, lili. Leakage of the pressure fluid. between the cylindrical member d@ and the bore d2 inY the header block is prevented by suitable packing rings Sli, @55 fitted in grooves in the cylindrical member, above and below the groove S2, Fig. l. A discharge pipe S3 is connected to the interior of the housing through a bore t!) the. base member i2.

The receiver block ld is made up of two parts lll, 'l2 which are fitted in a diametrically disposed groove le, formed in the upper side of the base member l2, and these parts are held in place in this groove by means of clamps l, Eli and screwsv '13, l, Figs. 2 and 4. The receiver block lil is provided with two openings 8i), di formed, respectively, in the parts lil, lf. As will be seen in Fig. 4, these openings are disposed symmetrically on the opposite sides of a vertical plane x-x which coincides with the meeting plane of the two receiver are formed by rectangular slots cut vertically through each of these parts, see also Fig. 5. On their lower sides, the receiver blockv parts le, l2 are each cut away at fill, 8G to connect the openings ell, 82, respectively, with angularly disposed passageways 88, @d in the base member. These passageways, in turn, open into vertically disposed bores 92, 94, in the base member, Figs. 4 and 5, and connected to these bores are discharge pipes BG, 98, Figs. l and 2.

At its lower end, the jet pipe f is fia tened out to the shape indicated in broken lines in Fig. 6 to form the jet nozzle 22. and its cylindrical bore is swaged to form an elongated rectangularly shaped orifice itil, also indicated by broken lines in Fig. 6. Just above the nozzle 22, a rectangularly shaped block H82 is iltted over and sweated to the j et pipe 2e. *EmbracingV this block and secured thereto by a screw ltd is a U-shaped yoke Illev havingv a pair of vertically extending sides les, im. Mounted on thebase member l2by means of a screw l I I, is a bracketmember H2' having a pair of upwardly extending arms lill, H5. Carried by these arms are a pair of leaf springs H8, im which extend on the opposite sides of, and are secured to the sides Hi8, il@ of the yoke llf. Fastened tothe housing lll, by means of a flange E22 and screws lill, is a gland i2@ in which there is mounted a plunger 25 which extends into the housing and is there connected to the flexible metal strip i3d and a connecting block 32. Secured to the outer end of this plunger, is a second flexible metal strip i3d.

In use, the inlet pipe bof the jet relay connected'to asuitablc source of fluid under pressure while the discharge pipes gli,` 9S are connected to the opposite ends of the fluid-pressureoperated motor the action of which is to beA controlled by the relay, and the overflow pipe 68V is connected to a sump. Also, the plungerl lZi is connected, by means of the flexible metal strip i3d, to asuitabieoperating mechanism such, for example, as one of the three operating mechanisms of thel machine disclosed inUnited States Letters Patent No. 2,644,968, granted July 14, 1953 upon application of IW alter L. Benedict,v Harryy D. CToodriowv and'Frank Pulsifer. As isfexplained, in

block parts lo, 1.2 andside H38 of the yokey lull by a.

that patent, each of these three operating mechanisms is actuated by a Work-engaging feeler and the jet relay controls the iiow of pressure fluid to a Huid-pressure-operated motor in such a Way as to maintain the work in a desired position as determined by the feeler. In such an arrangement, the jet relay functions as the controlling device of a closed loop servo mechanism in which the feed connections include the work and the work-engaging feeler. It will be understood, however, that the arrangement outlined above is suggested merely for purposes of illustration and that the jet relay of this invention is capable of use in other types of apparatus wherein the operation of a iluid-pressuie-operated motor is to be eiciently and dependably controlled in an extremely sensitive manner.

The jet pipe 20 is of such a length that the nozzle 22, at its lower end, may be readily displaced by lexing of the pipe. The arms H4, IIB of the bracket II 2 and the leaf `springs H8, I 20, which are connected at their vopposite ends to the aforementioned arms and also to the yoke member |05 which is associated with the nozzle, are so disposed as to urge the nozzle to a centered position, i. e., a position in which the elongated orifice I0@ of the nozzle 22 is symmetrically located with respect to the vertical plane xwhich passes through the inner edges of the reo eiver block openings 30, 32. These springs also f; nction as a pair of parallel links so that, when the nozzle is displaced in either direction from its centered position, by a force applied thereto through the plunger IM, it will be constrained to move in a direction substantially perpendicular to the plane and the orice will remain at all times substantially parallel to this plane, as well as substantially centered, in a lengthwise direction relatively to the opposite ends of the openings 30, 82 in the receiver block.

The openings 60, 02 are of rectangular shape, see Fig. 6, and are spaced apart between their adjacent ends by a distance approximately equal to their width. For the purpose of obtaining a sensitive control, these openings are quite narrow in width, while the width of the orice I 00 in the nozzle 22 is, as can be seen in Fig. 6, approximately one-third of the width of these openings. Preferably, and in the herein illustrated construction, the wall thickness of the jet pipe 20 when the nozzle is in its centered Fig. 6, there is a small gap of the nozzle and the outer the other of the openings 30, 82. clearance between the lower end of the nozzle 22 and the upper surface of the receiver block M is, in a manner which will be explained below, maintained at an absolute minimum value. Although the dimensions of the several parts, i. e., nozzle 22, openings 80, 82, orifice |00, and the clearance between the nozzle and the receiver blocks may, of course, be varied to accommodate different operating conditions, the dimensions Iof a jet relay of this type, which has proved to be very satisfactory in operation, are given below by way of an example: width ofl -openings B0, 82 (dimension a in Fig. 6) :.030 inch; length of openings approximately .125 inch; width of orifice I0@ (dimension b in Fig. 6) :.010 inch; length of orifice sufficient to overlap the opposite ends of the openings, as shown in Fig. 6; wall thickness of nozzle 22 (dimension d in Fig. 6) :.023 inch; width of gaps at the opposite sides of the nozzle when the nozzle is in centered position (dimension g in Fig. 6) :.002 inch, and

left between each side edge of one or The operating an operating clearance between the lower end of the nozzle and the upper side of the receiver plate (dimension e in Fig. 5) in the magnitude of .0001 inch. With a jet relay having the dimensions outlined above, an einciency, i. e., ratio of the maximum outlet pressure to the inlet pressure, of approximately 94%, was obtained with a capacity of approximately one and one-third gallons per minute at '750 lb./sq. in. inlet pressure.

The minimum operating clearance between the lower end of the nozzle 22 and the upper surface of the receiver block I4 is provided in the following manner. The base member I2, receiver block Ill, conduits I t', I3, and header block I6, and the jet pipe 20 and cylindrical member 4I), -are first accurately assembled in such a way that the distance from the upper end of the header block IS to the upper surface of the receiver block I4 is a few thousandths of an inch less than the distance from the lower surface of the ange 44 on the cylindrical member d@ to the lower end oi the jet nozzle 22. Next, the jet nozzle, jet pipe, and the cylindrical member 40, which have rst been accurately assembled, as above noted, are inserted down through the bore 42 in the header block I 6 and the cylindrical member 40 is itted into the bore 42 until the flange 44 rests upon a thin metallic shim 300, previously placed on the upper surface of the header block. This shim is selected from a number of standard nozzle 22 will exceed the distance from this flange to the upper surface of the receiver block by an amount which is somewhat less than onethousandth of an inch. Accordingly, the lower ing clearance between the lower end of the nozzle and the upper surface of the receiver block suficient to permit unrestricted movement o-f the nozzle relatively thereto. The foregoing procedure will result in the provision of a clearance space of such small magnitude that it can hardly be measured, but which is believed to be considerably less than .0001 inch. Also, the upper surface of the receiver block I4 will be lapped'to a very slightly cupped surface, in the vicinity of the lower end of the nozzle 22, and the radius of curvature of this surface will be substantially the same as the radius of curvature of the path of movement of the lower end of the nozzle. After the nozzle has thus been lapped in, the base member, carrying the conduits I8, the header block I0, the cylindrical member lil and the jet pipe 20, are inserted in the lower end of the housing I0 and secured thereto, and the cover plate is iitted over the header block I6 and secured in place on the upper end of the housing.

The extremely high operating eiciency of the herein illustrated jet relay is due primarily to the minimum operating clearance between the nozzle 22 and the receiver block Id, while the use of such a small operating clearance is made possible by the manner in which the jet relay is constructed. As is indicated by the arrows in Fig. 1, theV presamarte andthence downwardly to the nozzle 2.2i throughr the jetipipel, The conduits i8, i3 and jet pipe 2li areconstructed of materials having the same linear. coeflicientv of thermal expansion and are or; substantially the same length and of similar lcross-sectional shape and area. Also, the header block i6, which is supported on the upper ends of these conduits and to which the jet pipe is secured, isslidably tted in the bore 32 formed inithe'coverplate 28 ofthe housing Iii. Accordingly, when thetemperature of the operating fluid increases or decreases, during the operation of the jet', relay, the linear expansion of the conduits |3 l, permitted as the header block l slides in the bore 32, is exactly odset by the linear expansion ofthe jet pipe 2Q. Hence, under all operating conditions and with the full range of operating temperatures, the clearance between the nozzle and the receiver biocl: will remain constant.` Also, because of 'the cupped surface on the receiver block, formed during the lapping-in of the nozzle, this clearance will be maintained during displacement of the nozzle from its centered position.

The herein illustrated jet relay also affords extreme sensitivity of control and dependable operation. Referring to Fig. 6, it will be observed, when the-jet is in its centered position, that the pressure of the fluid in the two discharge pipes 95, 98 will be equalized and will be of. a magnitude which depends on the pressure of.r theiiuid admitted to the nozzle through the inlet pipe 59 and the relation between the volume of uid delivered to the two openings Sli, 82 and the amount exhausted through the gaps between the opposite sides of the nozzle andthe outer edges of these openings and between the nozzle and the upper surface of the receiver block.. Thus, the iluid-pressure-operated motor which is` connected to these discharge pipes, e. g., a piston in a cylinder, will be held stationary by iiuid under equal pressure applied to its opposite ends. This balance will, however, be disturbed, and movement of the motor in one direction or the other eiected by the slightest displacement of the nozzle 22V from its. centered position, as by aV force applied thereto by the plunger |225. For example, if the nozzle 22 is displaced, upwardly in Fig. 6 (to the right in Figs. l and 4), by an amount of .065 inch, the orice lilo will entirely overlap the opening Si), the gap between the upper side of the nozzle and the outer edge ofy the opening eil will be closed and the gap between thelower side of the nozzle and the outer edge of the opening 32 will be increased to .007 inch. Accordingly, the pressure of the fluid in the discharge pipe 95 will considerably exceed the pressure of the fluid in the discharge pipe 9S with the result that the iluid-pressure-operated motor, controlled by the jet relay, will be caused to operate in onedirection at a rate proportional to the difference between the pressures of the fluid inthese two pipes. Further displacement of the jet nozzle will, of course, increase the unbalancing of the pressures of the duid in these pipes and correspondingly increase the rate of movement of the iluid-pressure-operated motor up to a point (approximate displacement of the nozzle from centered position of .007 inch) where the diierence of the pressure of the fluid in the two discharge pipes 9%, S8 is at a maximum. In this connection, it may be pointed out that, with a header blocl: I6, fromthef relay' of the dimensions setvforth above, by way of' examplafurther movement of the nozzle beyond the .007 inch displacement point, results in only a very slight increase in this pressure difference and, for practical purposes, the maximum nozzle displacement is .007 inch. Thus, byy the nozzle 22 the a very slight displacement of operation of a fluid-pressure-operated motor may be directly and sensitively controlled.

inasmuch as the displacement of the nozzle 22 is effected, against the slight resistance of the leaf Springs llt, lZil, by flexing of the jet pipe 2d, the forces required to displace the nozzle are relatively small. Moreover, inasmuch as no'bear'- ings of any kind are used, all stickiness which might result from frictionin the bearings, is avoided and the forces required to move the nozzle remain uniform and proportional to the amount of nozzle displacement. Thus, therelation is most dependable-and consistent in operation;

Having thus described our invention, what we claim as new and desire to secure by Letters Patent of the United States is:

l. A. jet relay comprising a housing, member-a jet receiver ings associated with said base member, a pair of conduits mounted on the base member and extending upwardly withinl said housing, a headery block supported on said conduits, a flexible pipe secured to the header block and extending downwardly within said housing, said header block being provided with passageways for connecting said conduits to said flexible pipe, a jet nozzle carried on the lower end of said llexible pipe and provided with a discharge orifice positioned directly over and closely adjacent. to said jet receiver, and means extending through the housing for displacing said nozzle, relatively toV the openings in said jet receiver, by flexible pipe.

2. A jet relay comprising a housing, a base member associated with said housing, a iet rebending the ceiver block provided with a pair of openingsA and supported on said base member, a pair of conduits mounted on the base member and extending upwardly within said housing, a header block supported on the said conduitaa flexible pipe secured to the: header block and extending downwardly within the housing, said header block being provided with passagewaysfor connecting said conduits to saidexible pipe, a jet nozzle carried on the lower end of said flexible pipe and provided with a discharge orice positioned directly over and closely adjacent to said' receiver'bloclr, and means extending through said housing for displacing said nozzle, relatively to the openings in the receiver block, by bending the iiexible pipe.

3. A jet relay comprising a housing, a base member, a jet receiver including a pair of openings associated with said'base member, a pair of conduits mounted on the base member and extending upwardly within said housing, a header block supported on the up 3er ends of said conduits and slidably ntted in the housing, a ilexible pipe secured to the header block and extending downwardly within the housing, said header block being provided withpassageways for connecting said conduit-sto said flexible pipe, a jet nozzle carried on the lower end of said flexible pipe and.

ing for displacing said nozzle, relatively tosaid a baseincluding a pair of open-l 91 openings, said pair of conduits and said iiexible pipe being constructed of materials having substantially the same linear coefficient of expansion.

4. A jet relay comprising a housing, a base member associated with said housing, a receiver block supported on the base member, a pair of conduits mounted on the base member and extending upwardly within said housing,` a header block supported on the upper ends of said conduits and slidably fitted in the housing, a flexible pipe secured to the header block and extending downwardly within the housing, said header bloc-k being provided with passageways for connecting said conduits to said flexible pipe, a jet nozzle carried on the lower end of said nexible pipe and provided with a discharge orice positioned directly over and closely adjacent to said receiver block, and means extending through said housing for displacing said jet nozzle relatively to said openings, said pair of conduits and said ilexible pipe being constructed of materials having substantially the same linear coeiiicient of expansion.

5. A jet relay comprising a housing, a base member, a let receiver including a pair of openings associated with said base member, a pair of conduits mounted on the base member and extending upwardly within said housing, a header block supported on the upper ends of said conduits and slidably fitted in the housing, a pipe mounted on the header block and extending downwardly within the housing, said header block being provided with passageways for connecting said conduits to said pipe, a jet nozzle carried on the lower end of said pipe and provided with a discharge orifice positioned directly over and closely adjacent to said jet receiver, and means extending through said housing for displacing said nozzle, relatively to the openings in said `iet receiver, said pair of conduits and said pipe being constructed of materials having substantially the same linear coeiiicient of expansion.

l6. A jet relay comprising a housing, a base member, a receiver block provided with two openings and supported on said base member, a pair of conduits mounted on the base member and extending upwardly within said housing, a header block supported cn the upper ends of said conduits and slidably iitted in the housing, a pipe mounted on the header block and extending downwardly within the housing, said header block being provided with passageway-s for connecting said conduits to said pipe, a jet nozzle carried on the lower end of said pipe and provided with a discharge oriiice positioned directly over and closely adjacent to said jet receiver, and means extending through said housing for displacing said nozzle, relatively to the openings in said jet receiver, said pair of conduits and said pipe being constructed of materials having substantially the same linear coeiicient of expansion.

7. A jet relay comprising a housing, a base member, a jet receiver associated with said base member, a pair of conduits mounted on the base member and extending upwardly within said housing, a header block. supported on the upper ends of said conduits, a flexible pipe secured to the header block and extending downwardly within the housing, a jet nozzle secured to the lower end of said nexible pipe and provided with a discharge orifice positioned directly over and closely adjacent to said jet receiver, a pair of openings in the jet receiver disposed on the opto the aforementioned plane and against the resistance of said spring means.

8. A jet relay comprising a housing, a base member associated with said housing, a receiver block supported on the base member, a pair of conduits mounted on a base member and extending upwardly within said housing, supported on the upper ends of said conduits, a pipe secured to the header block and extending downwardly within the housing, a jet nozzle secured to the lower end of said pipe and pro-, vided with a discharge oriiice positioned directlyv over and closely adjacent to said receiver block,4 the receiver block on the a pair of openings in opposite sides of a plane substantially parallel to the longitudinal axis of said pipe, spring means associated with said base member and said nozzle arranged yieldingly to hold the nozzle in a position in which its discharge orice is centered with respect to said opening, and means extending through the housing and connected to the nozzle for displacing said nozzle, relatively to said openings, in directions normal to the aforementioned plane and against the resistance of said spring means.

9. .A iet relay comprising a housing, a base member associated with said housing, a receiver block supported on the base member, a pair of conduits mounted on the base member and ex. tending upwardly within said housing, a header upper ends of said con-.

block supported on the duits and slidably fitted in the housing, a flexible pipe secured to the header block and extending downwardly within the housing, a jet nozzle secured to the lower end of said exible pipe and, provided with a discharge oricepositioned di-, rectly over and closely adjacent to said receiver block, a pair of openings in the receiver block disposed on the opposite sides of a plane substantially parallel to the longitudinal axis of said flexible pipe, spring means associated with said base member and said jet nozzle arranged yieldingly to hold the nozzle in a position in which its discharge orifice is centered with respect to said openings, and means extending through the housing and connected to the nozzle for displacing said nozzle, relatively to said openings, in directions normal to the aforementioned plane and against the resistance of said spring means.

10. A jet relay comprising a housing, a base member, a `iet receiver associated with said base member, a pair of conduits mounted on the base member and extending upwardly within said housing, a header block supported on the upper ends of said conduits and slidably fitted in the housing, a pipe mounted on the header block and extending downwardly within the housing, a jet nozzle secured to the lower end of said pipe and provided with a discharge orice positioned directly over and closely adjacent to said jet receiver, a pair of openings in the jet receiver disposed symmetrically on the opposite sides of a plane substantially parallel to the longitudinal axis of said pipe, spring means associated with said base member and said jet nozzle arranged yieldingly to hold the nozzle in a position in which plane substantially parallel to a header block' its discharge orice is centered with respect -to said openingsand means extending through the housingand connected to .the nozzle for .displacing said nozzle, relatively to said openings, in directions normal to the aforementioned plane andagainst the resistance of said spring means,

ll. .A jet relay comprising a housing, .a base member, `a jet receiver associated with said base member .and provided with a pair of openings, symmetrically vdisposed on the opposite sides of a plane, a header block, a flexible pipe mounted on `the header bloei; and extending downwardly within .the housing, a jet .nozzle secured to the lower end of said pipeand provided with a discharge orifice, said orice being of elongated shape and of a length to overlap said openings at their opposite ends, means extending through the housing and connected to said nozzle for displacing the nozzle, relatively to said openings, by bending the liexble pipe, and meansiassociated with said base member and said nozzle for constraining it to move in a path perpendicular to said plane.

l2. A jet relay comprising a housing, a base member, a jet receiver associated with said base member .and provided with .a pair of openings, symmetrically disposed on the opposite sides of a plane, a -pair of conduits mounted on the base member and extending upwardly within the housing, a header block supported on said conduits and slidably fitted in the housing, a flexible pipe mounted on the header block and extending downwardly within the housing, a jet nozzle secured'to'the lower end of said pipe and provided with a discharge orice, said discharge vorice being of elongated shape and of a length to overlap said openings at their opposite ends, means extending through `the housing and connected to said nozzle for displacing the nozzle, relatively to said openings, by bendingthe flexible pipe, and means associatedwith said basemember and said nozzle for constraining it to move ina direction perpendicular to said plane.

'13. A -jet relay comprising a housing, a base member, 'a yjet receiver associated with said base member and provided with a pair of openings,

symmetrically disposed on the opposite sides-o a plane, -a header block, a Yflexible `pipe mounted on the header block and extending Adownwardly within the housing, a jet nozzle secured 4to lthe lower end of said pipe and provided with a discharge orice, said discharge orifice being of elongated shape and of a length to overlap said openings at their opposite ends, and means .extending through the vhousing and connected .to said nozzle for displacing the nozzle, relatively to said openings, by bending vthe flexible pipe, and spring means associated with said base member and said nozzle for constraining it to move in a direction perpendicular to said plane.

14. A jet relay comprising a housing, a rbase member, a jet receiver associated with said base member .and provided with a pair of openings, symmetrically disposed on the opposite sides of a plane, a pair of conduits mounted on the base member and extending upwardly within the'housing, a header block supported on said conduits and slidably iitted in the housing, a 'flexible rpipe mounted on the header block and extending downwardly within the housing, a jet nozzle secured to the lower end of said pipeand provided with a discharge orice, said discharge orifice being of elongated shape and of a length to overlap said openings at their opposite ends, means extending'throughthe housing and connected to said nozzle for displacing the nozzle, 'relatively to said openings, by bending the flexible pipe, and spring ymeans associated-with said 'base member and said nozzle for constraining it to `move in a direction perpendicular to said plane.

'WALTER L. VBENEDICT.

SIDNEY J. FINN.

References Cited in the le of this patent UNITED STATES PATENTS Number Name 'Date 2,308,662 Manteuffel Jan. 19, 1943 FOREIGN PATENTS Number Country Date 541,717 `Germany Jan. 18, 1932 

